1. Field of the Invention
The invention relates to a device for the cross perforation of webs, preferably paper webs for producing sacks. Said device comprises a rotatingly driven perforating blade and a grooved roller, both of which are mounted on a machine frame and between them passes the web to be perforated.
2. Description of the Related Art
For example, to produce paper sacks, paper tubes are produced from one web or several layers of webs, which are guided simultaneously, by folding in the sides so that they overlap and then by cementing the overlapping regions. From these paper tubes are severed socalled tubular segments. These tubular segments are then further processed in the conventional manner into paper sacks by forming the bottoms.
In so doing, the tubular segments are severed from the previously produced tubular web by providing cross perforations at intervals over the tubular segments so that the tubular segments can be torn off, one after the other, from the tubular web by the tear off devices.
These tubular segments are usually stacked into packages and passed on for the purpose of further processing into sacks.
As a function of the thickness of the paper webs or the number of layers of the tubular web to be perforated, the teeth of the perforating blade must descend deeper or less deeply into the grooved roller. Furthermore, it is desirable that for the purpose of feeding the perforated web, the perforating blade and the grooved roller be spaced so far apart that feeding does not cause a problem.